JP6819396B2 - Variable valve gear for internal combustion engine - Google Patents

Description

The present invention relates to a variable valve gear of an internal combustion engine.

As a conventional variable valve gear of an internal combustion engine, the one described in Patent Document 1 is known. In the one described in Patent Document 1, the protruding portion is brought into contact with the driven member between the cam and the intake valve, and the volume of the hydraulic chamber in the protruding portion is while the intake valve is lifted by the cam ridge of the cam. The valve lift amount is controlled by reducing the size of the cam and retracting the infested part to close the intake valve at an arbitrary timing.

Japanese Patent No. 5944125

In the variable valve gear of the internal combustion engine described in Patent Document 1, the cam may be maintained in a state where the swing arm is pushed when the internal combustion engine is stopped. When the internal combustion engine is stopped for a long time, the cam gradually pushes the swing arm for a long time, and the oil in the hydraulic chamber described in Patent Document 1 is discharged from the gap. The oil in the hydraulic passage of the internal combustion engine may return to the oil pan through the gap of the rotor of the oil pump downstream from the variable valve mechanism, and air may enter the hydraulic passage through the gap of the crank metal or the like. When the internal combustion engine is started in such a state, air may be contained in the oil when the oil is pumped from the oil pan to the variable valve mechanism.

When the internal combustion engine is started in such a state, the air in the oil passage is first filled in the hydraulic chamber of the variable valve mechanism. Therefore, it may take some time for air to be discharged from the hydraulic chamber and reach a desired valve lift amount as the hydraulic oil flows.

Therefore, it is desired to be able to obtain a desired valve lift amount at an early stage when the internal combustion engine is started.

The present invention has been made in view of the above problems, and is a variable operation of the internal combustion engine capable of quickly discharging air from the hydraulic chamber at the start of the internal combustion engine and obtaining a desired valve lift amount at an early stage. The purpose is to provide a valve device.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a variable valve gear for an internal combustion engine capable of starting an internal combustion engine having a variable valve mechanism in a short time.

In order to solve the above-mentioned problems and achieve the object, one aspect of the present invention is to contact a driven member that is displaced following a cam and the driven member, and the displacement of the driven member is transmitted. It has a valve that lifts to open the intake port or the exhaust port, a protruding portion that comes into contact with the driven member, and a hydraulic chamber that changes in volume with hydraulic oil and drives the protruding portion to appear and disappear in response to the volume change. While the valve is being lifted by the nose portion of the cam, the oil relief passage leading to the hydraulic chamber is opened, the volume of the hydraulic chamber is reduced, the infested portion is retracted, and the valve is moved at an arbitrary timing. The control unit includes a hydraulic actuator that closes and operates the oil relief passage, and a control unit that opens and closes the oil relief passage so as to discharge air in the hydraulic chamber when the internal combustion engine is started. In the air bleeding operation, the oil relief passage is held in an open state during the non-lift period in which the base circle portion of the cam and the driven member come into contact with each other and the valve does not lift. The first opening / closing control for keeping the oil relief passage closed is performed during the liftable period during which the nose portion of the cam and the driven member come into contact with each other and the valve can be lifted.

As described above, according to the above invention, when the internal combustion engine is started, air can be quickly discharged from the hydraulic chamber, and a desired valve lift amount can be obtained at an early stage.

FIG. 1 is a front view showing a non-lifting state when the base circle portion of the cam is in contact with the first input roller in the variable valve gear of the internal combustion engine according to the embodiment of the present invention. FIG. 2 is a cross-sectional view showing a protruding portion of the hydraulic actuator holding a protruding state in the variable valve gear of the internal combustion engine according to the embodiment of the present invention. FIG. 3 is a flowchart illustrating the operation performed by the ECU in the variable valve gear of the internal combustion engine according to the embodiment of the present invention. FIG. 4 is a timing chart illustrating a first opening / closing operation and a second opening / closing operation performed by the ECU in the variable valve gear of the internal combustion engine according to the embodiment of the present invention. FIG. 5 is a table of the number of operations referred to when the ECU performs the air bleeding operation A in the variable valve gear of the internal combustion engine according to the embodiment of the present invention.

The variable valve device of the internal combustion engine according to the embodiment of the present invention is an intake port or an exhaust port by contacting a driven member that displaces following a cam and the driven member and transmitting the displacement of the driven member. It has a valve that lifts to open, a protruding part that comes into contact with the driven member, and a hydraulic chamber that changes the volume with hydraulic oil and drives the hanging part to appear and disappear in response to the volume change, and the valve is provided by the nose portion of the cam. While the cam is being lifted, the oil relief passage leading to the hydraulic chamber is opened, the volume of the hydraulic chamber is reduced, the infested part is retracted, and the valve is closed at an arbitrary timing. When the internal combustion engine is started, the control unit performs an air bleeding operation to open and close the oil relief passage so as to exhaust the air in the hydraulic chamber, and in the air bleeding operation, the base circle of the cam and the control unit are provided. During the non-lift period when the valve does not lift due to contact with the driven member, the oil relief passage is kept open, and the liftable period during which the valve can be lifted by contact between the cam nose and the driven member. The first opening / closing control is performed so that the oil relief passage is closed. As a result, the variable valve gear of the internal combustion engine according to the embodiment of the present invention can quickly discharge air from the hydraulic chamber when the internal combustion engine is started, and can obtain a desired valve lift amount at an early stage.

The details of the variable valve gear of the internal combustion engine according to the embodiment of the present invention will be described below with reference to the drawings.
<Structure of variable valve gear>

The configuration of the variable valve gear 100 according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the variable valve gear 100 according to the present embodiment includes a variable valve mechanism 100A that changes the valve lift amount and an ECU (Electronic Control Unit) that electrically controls the variable valve mechanism 100A. 50 and.

The variable valve mechanism 100A includes an intake valve 4, a cam shaft 1, a cam 2 fixed to the cam shaft 1, and a support shaft 3 arranged on the side of the cam shaft 1 in parallel with the cam shaft 1. It includes a rocker arm 5 that opens and closes the intake valve 4 on the other end side according to the swing operation, a swing arm 6, a hydraulic actuator 20, an oil reserve tank 30 as an accumulator, and a solenoid valve 40.
(Intake valve)

The intake valve 4 is provided so as to be able to advance and retreat in the axial direction by a valve guide on the cylinder head side (not shown), and the upper end is pulled up by a valve spring 11 supported by the valve retainer 17 (closes the intake port 61 and the combustion chamber (not shown). Direction) is being urged.

The intake valve 4 is in contact with a valve seat (valve seat) 18 provided on the cylinder head side when the valve is closed. The intake valve 4 is in contact with the arm tip portion 5A of the rocker arm 5, and is lifted so as to open the intake port 61 by transmitting the displacement of the rocker arm 5.
(cam)

The cam shaft 1 is rotatably supported by a bearing portion on the cylinder head side (not shown), and is rotated in conjunction with a crankshaft (not shown) by a chain, belt, or the like (not shown).

The rotation speed of the cam shaft 1 is set to be, for example, 1/2 of the rotation speed of the crankshaft. Further, in the present embodiment, the cam shaft 1 is arranged so as to extend along the front-rear direction (the direction penetrating the paper surface of FIGS. 1 and 2) of the internal combustion engine (not shown).

The cam 2 has a base circular portion 2A as a base and a nose portion 2B formed so as to bulge outward from the base circular portion 2A. The cam 2 is integrally provided by press-fitting and fitting the cam shaft 1 to the center of the base circular portion 2A.

Therefore, the arrangement state of the cam 2 with respect to the cam shaft 1 defines the lift start timing of the intake valve 4 that operates with the operation of the crankshaft (not shown).
(Rocker arm)

One end of the rocker arm 5 is swingably supported by the support shaft 3. A swing arm 6 is pivotally supported at the center of the rocker arm 5 so as to swing. An adjusting screw 9 that abuts on the upper end of the intake valve 4 is fastened to the arm tip 5A on the other end side of the rocker arm 5 with a lock nut 10 so as to project downward.

By adjusting the length of the adjusting screw 9 protruding downward from the arm tip portion 5A, the operation timing of the intake valve 4 can be appropriately adjusted, and the operation timing between the cylinders can be matched. A detected portion 5B is provided on one end side of the rocker arm 5 at a position facing the gap sensor 7 provided on the cylinder head side (not shown).
(Swing arm)

The intermediate portion of the swing arm 6 is pivotally supported by a fulcrum arm pin 8 as a rotation axis with respect to the rocker arm 5. The swing arm 6 includes an arm plate 12 bent at a pair of intermediate portions.

A cylindrical first input roller 15 as a first contact portion is interposed between one ends of the pair of arm plates 12, and the first input roller 15 is rotatably supported by a first roller pin 16. ing.

Further, a cylindrical second input roller 13 as a second contact portion is interposed between the other ends of the pair of arm plates 12. The second input roller 13 is rotatably supported by a second roller pin 14.

The first input roller 15 is set so that the cam surface of the cam 2 is in constant contact with the cam surface. The second input roller 13 is set so as to be in constant contact with the protruding portion 23 of the hydraulic actuator 20, which will be described later. The rocker arm 5 and the swing arm 6 form a driven member 60 that is displaced following the cam 2.
(Flood actuator)

As shown in FIG. 2, the hydraulic actuator 20 used in this embodiment is slidably fitted to the guide cylinder 21 having the first hydraulic chamber constituent pipe 21A coaxially inside and the first hydraulic chamber constituent pipe 21A. It is configured to include a piston 22 provided with a second hydraulic chamber constituent pipe 22A.

Further, the hydraulic actuator 20 is interposed between the guide cylinder 21 and the piston 22 and the cylindrical container-shaped protruding portion 23 that is slidably fitted to the guide cylinder 21 with the piston 22 housed in the piston 22 and the protruding portion. It is configured to include a return spring 24 that urges the 23 in a direction protruding from the guide cylinder 21.

Further, the hydraulic actuator 20 is provided via an oil passage case 25 provided on the upper portion of the guide cylinder 21 and communicating with the first hydraulic chamber constituent pipe 21A, a check valve 26 provided in the oil passage case 25, and a check valve 26. An oil supply passage 27 communicating with the oil passage case 25 and an oil pump 28 connected to the oil supply passage 27 are provided.

The internal space formed by the first hydraulic chamber constituent pipe 21A and the second hydraulic chamber constituent pipe 22A constitutes the hydraulic chamber 29. An inlet portion 25A communicating with the oil supply passage 27 is formed in the upper portion of the oil passage case 25. Further, an outlet portion 25B is formed on the side portion of the oil passage case 25. An oil relief passage 31 through which hydraulic oil can flow communicates with the outlet portion 25B.

The check valve 26 includes a check ball 26A, a mortar-shaped holding plate 26B having a distribution hole formed in the center for holding the check ball 26A, and a check ball retainer 26C arranged on the downstream side of the check ball 26A. ing.

Further, the check valve 26 includes a check ball return spring 26D that is interposed between the check ball retainer 26C and the guide cylinder 21 and is urged to push up the check ball retainer 26C.

In the hydraulic actuator 20, the protruding portion 23 is in contact with the second input roller 13 of the swing arm. The volume of the hydraulic chamber 29 changes due to the hydraulic oil, and the infestation portion 23 is driven in and out according to the volume change.

The hydraulic actuator 20 opens the oil relief passage 31 leading to the hydraulic chamber 29 while the valve is being lifted by the nose portion 2B of the cam 2, reduces the volume of the hydraulic chamber 29, retracts the infestation portion 23, and takes in air. The valve 4 is closed at an arbitrary timing.
(Oil reserve tank and solenoid valve)

The oil reserve tank 30 is interposed between the cylinder 32 through which the oil relief passage 31 communicates at the lower part, the piston 33 housed in the cylinder 32, and the upper inner wall of the cylinder 32 and the piston 33, and connects the piston 33 to the cylinder 32. It is configured with a spring 34 that urges the lower inner wall of the cylinder. An air bleeding hole 32A is formed in the upper part of the cylinder 32. Further, an oil relief hole 32C is formed at a predetermined height position of the side wall 32B of the cylinder 32.

The plunger 41 of the solenoid valve 40 appears in the oil relief passage 31 to open and close the oil relief passage 31. The solenoid valve 40 is controlled by the ECU 50 based on the control program stored in the ECU 50 and the output signal of the gap sensor 7 that detects the distance from the detected portion 5B provided on the rocker arm 5. .. That is, the ECU 50 controls the opening and closing of the oil relief passage 31 by controlling the appearance of the solenoid valve 40.
(Variable valve device lift amount changing operation)

Next, the lift amount changing operation of the variable valve gear 100 according to this embodiment will be described.
(When the maximum lift amount is selected)

When the setting of the maximum lift amount is selected, the volume in the hydraulic chamber 29 is in the maximum state as shown in FIG. Further, the solenoid valve 40 is in a state in which the oil relief passage 31 is closed, and the hydraulic oil is in a state in which backflow is blocked by the check valve 26. Therefore, in this state, the protruding portion 23 that operates together with the piston 22 of the hydraulic actuator 20 is held in a protruding state.

In the non-operating state of the intake valve 4, as shown in FIG. 1, the first input roller 15 in contact with the base circle 2A of the cam 2 has the cam 2 in the direction of arrow a (clockwise in the drawing). Even if it rotates, the first input roller 15 only rolls and is in a state where it does not receive pressing force from the cam 2 side.

When the rotation of the cam 2 in the direction of the arrow a progresses from this state, the nose portion 2B of the cam 2 comes into contact with the first input roller 15 and the first input roller 15 is pressed and pushed down. When the first input roller 15 is pushed down, the swing arm 6 rotates clockwise in the drawing with the second input roller 13 as a fulcrum.

Since the intermediate portion of the swing arm 6 is supported by the rocker arm 5 by the fulcrum arm pin 8, the rocker arm 5 rotates clockwise in the drawing with the support shaft 3 as the fulcrum. Then, the adjusting screw 9 provided at the arm tip portion 5A of the rocker arm 5 presses the upper end of the intake valve 4, and the intake valve 4 is pushed down until the maximum lift amount Lmax is reached against the repulsive force of the valve spring 11. ..

From this state, when the cam 2 further rotates in the direction of arrow a, the nose portion 2B passes through the first input roller 15, and the base circle portion 2A comes into contact with the first input roller 15 again, the swing arm 6 is shown in FIG. Return to the indicated state (position). Along with this operation, the arm tip portion 5A of the rocker arm 5 rises, and the intake valve 4 rises due to the urging force of the valve spring 11 and is closed.
(When the minimum lift amount is selected)

Next, when the setting of the minimum lift amount (Lmin) of the intake valve 4 is selected when the load and the rotation speed of the internal combustion engine are in the predetermined operating range, the intake valve 4 is not operating (valve lift has occurred). The state of (when not present) is the same as the state shown in FIG.

As shown in FIG. 1, in the non-operating state of the intake valve 4 (the state in which the base circle portion 2A of the cam 2 is in contact with the second input roller 15), even if the cam 2 rotates in the direction of the arrow a. The second input roller 15 is in a state where it only rolls and does not receive pressing force from the cam 2 side.

At this time, as shown in FIG. 2, the volume in the hydraulic chamber 29 is in the maximum state, the plunger 41 of the solenoid valve 40 is in the state where the oil relief passage 31 is closed, and the hydraulic oil is in the check valve 26. The backflow is blocked.

Therefore, the protruding portion 23 that operates together with the piston 22 of the hydraulic actuator 20 is held in a protruding state.

After that, when the rotation of the cam 2 in the direction of the arrow a progresses with the protruding portion 23 protruding, the base of the nose portion 2B of the cam 2 comes into contact with the first input roller 15 and gradually presses the first input roller 15. Begin to.

Therefore, the swing arm 6 rotates clockwise in the drawing with the second input roller 13 as a fulcrum. Since the intermediate portion of the swing arm 6 is supported by the rocker arm 5 by the fulcrum arm pin 8, in the state where the second input roller 13 is supported by the protruding portion 23 in this way, the rocker arm 5 uses the support shaft 3 as a fulcrum. It rotates clockwise in the figure. Then, the adjusting screw 9 provided at the tip of the arm 5A presses the upper end of the intake valve 4 and pushes down the intake valve 4 against the repulsive force of the valve spring 11.

Then, when a predetermined position on the way to the top of the nose portion 2B of the cam 2 comes into contact with the first input roller 15, the intake valve 4 becomes the preset minimum lift amount Lmin. With the minimum lift amount selected, the ECU 50 outputs a control signal for releasing the oil relief passage 31 to the solenoid valve 40 based on the output value of the control program and the gap sensor 7 stored in the ECU 50 to the solenoid valve 40. The valve 40 is set to turn on. Then, the plunger 41 of the solenoid valve 40 is sunk to open the oil relief passage 31.

When the oil relief passage 31 is opened, the hydraulic oil in the hydraulic chamber 29 can be moved to the oil reserve tank 30 via the oil relief passage 31.

At this time, the rocker arm 5 is pressed in the counterclockwise direction in the drawing by the urging force of the valve spring 11 with the support shaft 3 as a fulcrum. Along with this, the swing arm 6 is pressed in the clockwise direction in the drawing with the first input roller 15 in contact with the cam surface of the cam 2 as a fulcrum.

Therefore, the second input roller 13 of the swing arm 6 presses the protruding portion 23 so as to push it up. As the infestation portion 23 rises, the second hydraulic chamber constituent pipe 22A of the piston 22 in the infestation portion 23 rises in a state of being fitted to the first hydraulic chamber constituent pipe 21A on the guide cylinder 21 side, and the hydraulic chamber 29 rises. Reduce the volume.

Here, at the inlet portion 25A of the oil passage case 25, since the check valve 26 prevents the backflow, the hydraulic oil is sent from the outlet portion 25B of the oil passage case 25 to the oil relief passage 31.

Then, when the hydraulic oil is sent out to the oil relief passage 31, the oil reserve tank 30 pushes up the piston 33 against the urging force of the spring 34 to push the hydraulic oil into the space between the cylinder 32 under the piston 33. Save.

In the oil reserve tank 30, the air in the cylinder 32 is discharged from the air bleeding hole 32A as the piston 33 rises, and when the piston 33 descends, the space flows into the cylinder 32 from the air bleeding hole 32A. It has become.

In the oil reserve tank 30, when the piston 33 rises above the oil relief hole 32C, hydraulic oil is discharged and recovered from the oil relief hole 32C. By opening the oil relief passage 31 in this way, the infested portion 23 of the hydraulic actuator 20 can be suddenly raised. Therefore, the intake valve 4 can be closed quickly, and the effect of reducing the pump loss can be enhanced.

In this way, the variable valve gear 100 is swingably supported by the support shaft 3, and the rocker arm 5 that opens and closes the intake valve in accordance with the swing operation, and the rocker arm 5 has an intermediate portion that swings on the rotation shaft. A swing arm 6 that is freely pivotally supported and has a first input roller 15 as a first contact portion and a second input roller 13 as a second contact portion is provided at a position sandwiching the rotation shaft.

Further, the variable valve gear 100 includes a cam 2 which is fixed to a cam shaft 1 arranged in the vicinity of the first input roller 15 and which comes into contact with the first input roller 15 to allow the intake valve 4 to be lifted. There is. Further, the variable valve gear 100 includes a hydraulic chamber 29 which has a protruding portion 23 in contact with the second input roller 13, changes in volume due to hydraulic oil, and drives the protruding portion 23 in and out in response to the volume change. While the intake valve 4 is being lifted by the cam ridge (nose portion 2B) of the cam 2, the volume of the hydraulic chamber 29 is reduced, the infested portion 23 is retracted, and the intake valve 4 is closed at an arbitrary timing. It includes an actuator 20.
(Air bleeding operation of variable valve gear)

In this variable valve gear 100, air may be mixed into the hydraulic chamber 29 and the oil supply passage 27 while the internal combustion engine is stopped. If the internal combustion engine is started with air mixed in the hydraulic chamber 29, it takes time for the air to be discharged from the hydraulic chamber 29 and the engine speed to rise to a normal speed.

Therefore, in the present embodiment, when the internal combustion engine is started, the ECU 50 performs an air bleeding operation for opening and closing the oil relief passage 31 so as to discharge the air in the hydraulic chamber 29 according to a predetermined condition. ..

The air bleeding operation performed by the ECU 50 will be described with reference to FIG. In FIG. 3, the ECU 50 repeatedly determines in step S1 whether or not the engine is starting, and if it is in step S2, determines whether or not the engine is starting from the idle stop.

Here, the start of the internal combustion engine includes a restart from an idle stop and a normal start by a start operation. It is highly possible that the internal combustion engine was stopped for a short time when restarting from the idle stop, and that the internal combustion engine was stopped for a long time during normal starting by the starting operation. The longer the internal combustion engine is stopped, the more air may be mixed in the hydraulic chamber 29 and the oil supply passage 27.

When it is determined in step S2 that the engine is starting from the idle stop, the ECU 50 determines in step S3 whether or not the engine speed is equal to or higher than the predetermined speed. This is to determine whether the fuel injection / ignition cut is performed by the idle stop determination or the fuel injection / ignition cut is performed by the idle stop determination when the vehicle is stopped at a speed equal to or lower than the speed determined during deceleration / movement. Here, the oil pump 28 of the present embodiment is operated by rotating the internal combustion engine, and is adapted to supply sufficient oil pressure when the engine speed is equal to or higher than a predetermined speed. Therefore, in step S3, the ECU 50 determines whether or not the engine rotation speed is equal to or higher than the predetermined rotation speed, thereby grasping whether or not sufficient oil pressure is supplied from the oil pump 28 to the hydraulic chamber 29. It has become.

The ECU 50 ends the current operation when the engine speed is equal to or higher than the predetermined rotation speed in step S3, and performs the air bleeding operation B in step S4 when the engine speed is less than the predetermined rotation speed in step S3.

The air bleeding operation B is an operation of opening and closing the oil relief passage 31 so as to discharge the air in the hydraulic chamber 29, and includes the first opening / closing control shown in FIG.

As shown in FIG. 4, in the first opening / closing control, the non-lift period (the period before time t1 and the time t3) in which the base circle portion 2A of the cam 2 and the driven member 60 come into contact with each other and the intake valve 4 does not lift is performed. During the later period), the oil relief passage 31 is held in an open state, and the nose portion 2B of the cam 2 and the driven member 60 come into contact with each other to lift the intake valve 4 during a liftable period (time from time t1 to time). The period of t3) is a control for closing the oil relief passage 31.

By implementing this first opening / closing control, the hydraulic oil containing air in the hydraulic chamber 29 and the oil supply passage 27 is discharged into the oil relief passage 31 during the non-lift period in which the oil relief passage 31 is held in an open state. Can be discharged through.

Further, during the liftable period in which the oil relief passage 31 is closed, the protruding portion 23 can be maintained in a protruding state, and the intake valve 4 can be lifted. Therefore, it is possible to achieve both the discharge of air and the autonomous rotation of the internal combustion engine.

As described above, in the first open / close control, the hydraulic oil containing air can be discharged during the non-lift period while enabling the lift of the intake valve 4 during the liftable period. Therefore, the first open / close control is suitable for a situation where the stop time of the internal combustion engine is not long and the amount of air contained in the hydraulic oil is not large.

When the ECU 50 determines in step S2 that the engine is not started from the idle stop, the ECU 50 determines in step S5 whether or not the engine water temperature is equal to or lower than the predetermined water temperature.

The determination in step S5 is performed to grasp whether or not the internal combustion engine has been stopped for a long time, and when the engine water temperature is equal to or lower than the predetermined water temperature, the internal combustion engine has been stopped for a long time and the flood control This means that there may be a lot of air mixed in the chamber 29.

When the ECU 50 determines in step S5 that the engine water temperature exceeds the predetermined water temperature, the internal combustion engine has not stopped for a long time, so the above-mentioned step S4 is performed in the same manner as when restarting from the idle stop.

When the ECU 50 determines in step S5 that the engine water temperature is equal to or lower than the predetermined water temperature, the internal combustion engine has been stopped for a long time, so the air bleeding operation A is performed in step S6.

The air bleeding operation A is an operation of opening and closing the oil relief passage 31 so as to discharge the air in the hydraulic chamber 29. The second opening / closing control shown in FIG. 4 is performed, and the first opening / closing control is performed after the completion of the second opening / closing control. Do.

As shown in FIG. 4, the second open / close control controls the non-lift period (the period before the time t1 and the period after the time t3) and the period before the maximum lift time in the liftable period (time t1 to time t2). The oil relief passage 31 is kept open during the period), and the oil relief passage 31 is closed during the period after the maximum lift in the liftable period (the period from time t2 to time t3). This is the control for performing the second opening / closing control.

By implementing this second opening / closing control, the oil relief passage 31 is held in an open state during the non-lift period, so that the air in the hydraulic chamber 29 and the oil supply passage 27 is maintained in the same manner as in the first opening / closing control. The hydraulic oil containing the above can be discharged through the oil relief passage 31.

Further, by keeping the oil relief passage 31 in the open state in the period before the maximum lift in the liftable period, the infestation portion 23 can be submerged and the hydraulic chamber 29 can be reduced, and the hydraulic oil containing air can be discharged. It can be efficiently discharged from the hydraulic chamber 29.

Further, by closing the oil relief passage 31 in the period after the maximum lift in the liftable period, the infestation portion 23 can be projected again to expand the hydraulic chamber 29, and the oil supply passage 27 can be used. The inside of the hydraulic chamber 29 can be replaced with hydraulic oil containing no air.

In other words, the second open / close control is a control capable of realizing a pumping operation for reducing and expanding the hydraulic chamber 29, and the pumping operation enables efficient air discharge.

As described above, the second opening / closing control is a control that gives priority to promptly discharging the hydraulic oil containing air rather than lifting the intake valve 4. Therefore, the second open / close control is suitable for a situation where the internal combustion engine has a long stop time and the hydraulic oil may contain a large amount of air.

The lower the engine water temperature, the more the ECU 50 performs the second opening / closing control in the air bleeding operation A in step S6. The first reason is that the lower the engine water temperature, the longer the internal combustion engine has stopped, and the more air may be mixed in the hydraulic chamber 29 and the oil supply passage 27, and the lower the engine water temperature. It is based on the second reason that the fluidity of the hydraulic oil becomes lower and it becomes difficult to remove the hydraulic oil containing air from the hydraulic chamber 29.

The ECU 50 determines the number of times to perform the second open / close control with reference to the operation number table shown in FIG. This operation number table has been obtained in advance by experiments and the like, and is stored in the ROM in the ECU 50.

In the operation frequency table of FIG. 5, it is stipulated that the second open / close control is performed twice when the engine water temperature is 60 [° C.], and the second open / close control is performed 5 when the engine water temperature is -30 [° C.]. It is stipulated to do it once. The number of times of the second opening / closing control is counted with one rotation of the cam shaft 1 as one time.

For example, when the second opening / closing control is performed twice, the second opening / closing control is executed during the period in which the cam shaft 1 rotates twice. The number of executions may be determined by the number of times the crankshaft (not shown) of the internal combustion engine has rotated. Since the rotation speed of the cam shaft 1 is 1/2 of the rotation speed of the crankshaft, the number of executions based on the number of rotations of the crankshaft is set to twice the number of executions based on the number of rotations of the camshaft 1.

After the air bleeding operation B is performed in step S4 or the air bleeding operation A is performed in step S6, the ECU 50 determines in step S7 whether or not the valve lift amount is a predetermined normal lift amount.

When the ECU 50 determines in step S7 that the valve lift amount has not reached a predetermined normal lift amount, the ECU 50 returns to step S2. When the ECU 50 determines in step S7 that the valve lift amount has reached a predetermined normal lift amount, the ECU 50 ends the air bleeding operation A and the air bleeding operation B, and ends the flowchart of FIG.

In this embodiment, the variable valve gear 100 controls the opening and closing of the intake valve 4, but the variable valve gear 100 may control the opening and closing of an exhaust valve (not shown). ..

As described above, in the variable valve gear 100 according to the present embodiment, the ECU 50 performs an air bleeding operation B for opening and closing the oil relief passage 31 so as to discharge the air in the hydraulic chamber 29 when the internal combustion engine is started.

The ECU 50 keeps the oil relief passage 31 open during the non-lift period in which the intake valve 4 does not lift due to contact between the base circle portion 2A of the cam 2 and the driven member 60 in the air bleeding operation B, and the cam During the liftable period in which the intake valve 4 can be lifted by contacting the nose portion 2B of 2 and the driven member 60, the first open / close control is performed to keep the oil relief passage 31 closed.

As a result, when the internal combustion engine is started, the hydraulic oil containing air can be discharged from the hydraulic chamber 29 through the oil relief passage 31 by keeping the oil relief passage 31 open during the non-lift period.

Further, by closing the oil relief passage 31 during the liftable period, the intake valve 4 can be lifted and opened, and the autonomous rotation of the internal combustion engine can be maintained. Therefore, a normal valve lift amount can be quickly obtained when the internal combustion engine is started, and the rotation speed of the internal combustion engine can be increased in a short time.

As a result, when the internal combustion engine is started, air can be quickly discharged from the hydraulic chamber, and a desired valve lift amount can be obtained at an early stage.

Further, in the variable valve gear 100 according to the present embodiment, when the water temperature of the cooling water is equal to or lower than the predetermined water temperature at the time of normal start, the ECU 50 performs the air bleeding operation A during the non-lift period and the maximum lift during the liftable period. During the previous period, the oil relief passage 31 was held in an open state, and during the period after the maximum lift in the liftable period, the oil relief passage 31 was closed. 2 After the opening / closing control is completed, the first opening / closing control is performed.

As a result, if the temperature of the cooling water is low at the time of normal start of the internal combustion engine, there is a possibility that a large amount of air has entered the hydraulic chamber 29 in the infestation portion 23 because the internal combustion engine has been stopped for a long time. By performing the second opening / closing control before the first opening / closing control, the air in the hydraulic chamber 29 can be more preferably discharged.

Further, in the variable valve gear 100 according to the present embodiment, the ECU 50 increases the number of times of performing the second opening / closing control as the water temperature becomes lower.

As a result, as the water temperature of the internal combustion engine is lower, the number of times the second opening / closing control is performed is increased, so that air can be more preferably discharged from the inside of the hydraulic chamber 29.

Further, in the variable valve gear 100 according to the present embodiment, the ECU 50 ends the air bleeding operations A and B when the lift amount of the intake valve 4 reaches a predetermined normal lift amount when the internal combustion engine is started.

As a result, the air bleeding operations A and B are continued until the normal lift amount is obtained, so that the starting time of the internal combustion engine can be shortened more accurately.

Although the embodiments of the present invention have been disclosed, it is clear that some skilled in the art can make changes without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

100 ... variable valve device, 2 ... cam, 2A ... base circle, 2B ... nose, 4 ... intake valve (valve), 20 ... hydraulic actuator, 23 .. Haunting part, 29 ... hydraulic chamber, 31 ... oil relief passage, 50 ... ECU (control part), 60 ... driven member, 61 ... intake port

Claims (4)

A driven member that displaces following the cam,
A valve that comes into contact with the driven member and lifts to open the intake port or the exhaust port by transmitting the displacement of the driven member.
It has a protruding portion that comes into contact with the driven member, and a hydraulic chamber that changes in volume due to hydraulic oil and drives the protruding portion to appear and disappear in response to the volume change, and the valve is lifted by the nose portion of the cam. In between, a hydraulic actuator that opens an oil relief passage leading to the hydraulic chamber, reduces the volume of the hydraulic chamber, retracts the infested portion, and closes the valve at an arbitrary timing.
A control unit that controls the opening and closing of the oil relief passage is provided.
When the internal combustion engine is started, the control unit performs an air bleeding operation for opening and closing the oil relief passage so as to discharge air in the hydraulic chamber.
In the air bleeding operation, during the non-lift period in which the base circular portion of the cam and the driven member come into contact with each other and the valve does not lift, the oil relief passage is kept open and the nose portion of the cam A variable valve operating device for an internal combustion engine, characterized in that a first opening / closing control is performed to keep the oil relief passage closed during a liftable period in which the valve can be lifted in contact with the driven member. The start time of the internal combustion engine is the time of restarting from the idle stop system or the time of normal start-up by the start operation.
The control unit is used when the temperature of the cooling water is equal to or lower than the predetermined water temperature at the time of the normal start.
In the air bleeding operation
The oil relief passage is kept open during the non-lift period and the period before the maximum lift in the liftable period, and the oil relief is in the period after the maximum lift in the liftable period. Performs the second open / close control to close the passage,
The variable valve gear for an internal combustion engine according to claim 1, wherein the first opening / closing control is performed after the completion of the second opening / closing control. The control unit
The variable valve gear for an internal combustion engine according to claim 2, wherein the lower the water temperature, the more times the second opening / closing control is performed. The control unit is used when the internal combustion engine is started.
The variable valve gear for an internal combustion engine according to any one of claims 1 to 3, wherein the air bleeding operation is terminated when the lift amount of the valve reaches a predetermined normal lift amount.